Non-ferrous group VIII aluminum coprecipitated hydrogenation catalysts

ABSTRACT

Supported coprecipitated catalyst comprised of aluminum and metals from Group VIII and Groups IIA of the Periodic Table of the Elements are disclosed. The catalyst are produced by preparing an aqueous mixture containing the ions of said metals, aluminum ions, and solid porous support particles to form a reaction mixture of the metal ions and aluminum ions with the solid porous support particles. The reaction mixture is heated and a precipitating agent added to coprecipitate solid support particles.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part application of U.S. Ser. No.91,835, filed Nov. 6, 1979, now U.S. Pat. No. 4,273,680.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to supported coprecipitated metal-aluminumcatalyst wherein the metal is selected from the group consisting of thenon-ferrous metals of Group VIII of the Periodic Table of Elements.These catalysts are useful in hydrogenating organic compounds.

2. Description of the Prior Art

The catalytic reduction of organic compounds in the presence of one ormore metals of Group VIII of the Periodic Table of the Elements,particularly nickel and cobalt as well as nickel-cobalt ornickel-cobalt-copper catalysts is known. For example, U.S. Pat. No.3,320,182 teaches the preparation of a coprecipitated catalyst by slowlyadding ammonium bicarbonate to an aqueous solution containing nickelnitrate and aluminum nitrate at elevated temperatures. These catalystsare taught to have a reduced nickel surface area of 20-30 m² /g ofcatalyst. The coprecipitation of nickel salts from an aqueous solutionseeded with porous silica or porous alumina is taught in U.S. Pat. No.3,371,050. This '050 patent discloses a precipitation process whereinnickel nitrate is precipitated from an aqueous solution containingeither porous silica or gamma alumina particles. Example 10 of the '050patent discloses the coprecipitation of nickel and silicate ions from anaqueous solution seeded with porous silica. Example 11 of the '050patent teaches that the addition of copper salts to the aqueous solutionwill promote the nickel catalyst in Town Gas production. The nickelsurface area of such catalysts is disclosed as ranging from 40-60 m² /gof catalyst.

D. J. C. Yates, W. F. Taylor and J. H. Sinfelt (J. Am. Chem. Soc., 86,2996 [1964]) described a chemisorption technique and its utility incorrelating nickel particle size (and/or nickel surface area) withcatalytic activity. In FIG. 3 of their publication, there is shown thata direct relation exists between reduced nickel surface area (m² /g ofcatalyst) and initial reaction rate for ethane catalytically convertedinto methane (as mmols C₂ H₆ converted per hour per gram of catalyst).It follows, then, that methods which increase the nickel surface area ofa nickel catalyst (other factors such as nickel content remainingconstant) is a desirable feature, leading to a catalyst of improvedcatalytic activity. Patentees of U.S. Pat. Nos. 3,697,445; 3,859,370 and3,868,332 also appreciated that by achieving a higher degree ofdispersion of nickel in the catalyst results in a more active catalystand indeed they obtain a fairly high degree of dispersion by theircoprecipitation techniques wherein nickel cations were graduallyprecipitated from an aqueous solution in the presence of silicate anionand solid porous particles to obtain dispersion greater than 70 m² /g ofreduced nickel metal per gram of catalyst. Belgium Pat. No. 841,812teaches that the addition of copper ions during the precipitation stepprovides a catalyst that can be reduced at temperatures of approximately200° C. U.S. Pat. No. 4,088,603 discloses an improved method ofactivating the coprecipitated nickel-copper-silica catalysts.

A number of patents have disclosed cobalt, cobalt-nickel andcobalt-nickel-copper catalysts, e.g., U.S. Pat. Nos. 3,166,491;3,385,670; 3,432,443; 3,547,830; 3,650,713; 3,661,798; 3,945,944;4,014,933 and 4,026,823; and British Pat. Nos. 1,000,828; 1,000,829;1,095,996; 1,095,997 and 1,182,829. None of these patents, however,disclose coprecipitation of one or more Group VIII metal ions andaluminum ions in the presence of solid porous support particles.

Recently, U.S. Pat. No. 4,113,658 has disclosed a method for thecontrolled dispersion of metal on a coprecipitated catalyst. Forexample, nickel nitrate and support particles are coprecipitated bygradually increasing the alkalinity of the aqueous reaction mixture.

SUMMARY OF THE INVENTION

In accordance with the present invention, a supported coprecipitatedmetal-aluminum catalyst is prepared wherein the metal portion of thecatalyst is one or more metals selected from the group consisting of thenon-ferrous metals of Group VIII of the Periodic Table of the Elements.The catalysts of the present invention are characterized as having aB.E.T. total surface area ranging from about 150 to about 350 m² /g. Thetotal amount of the non-ferrous Group VIII metal in the catalyst rangesfrom about 25 wt. % to about 70 wt. % based on the total weight of thecalcined and reduced catalyst.

The catalysts of the present invention are prepared by:

(a) preparing a heated aqueous reaction mixture comprised of (i) atleast one water-soluble metal salt of a metal selected from the groupconsisting of non-ferrous metals of Group VIII of the Periodic Table ofElements; (ii) a water soluble aluminum salt; and (iii) solid poroussupport particles; and

(b) adding a precipitating agent to the heated reaction mixture tocoprecipitate the metal ions and aluminum ions with the solid poroussupport particles. The heated aqueous reaction mixture may be preparedby either mixing hot solutions of the salts and the solid supportparticles or by mixing the reaction mixture ingredients under ambienttemperature conditions and thereafter heating the reaction mixture toelevated temperatures, preferably at temperatures greater than 60° C.,and more preferably at temperatures ranging from 75° C., to the boilingpoint of the reaction mixture at atmospheric pressure. Preferably, thereaction mixture is vigorously agitated or mixed and maintained atelevated temperatures for a brief period of time, e.g., one to fivehours. The heating step may be conducted at ambient pressures orelevated pressures (i.e., to reduce evaporation). Followingprecipitation the catalyst can then be washed, dried, and calcined. Ifdesired, the calcined catalyst can be activated by reduction.

The catalyst may include up to about 10 wt. %, based on the total weightof the catalyst, of various additives such as metals selected fromGroups IB and IIA of the Periodic Table of the Elements. These additivesmay be included in the catalyst by coprecipitation of their salts withthe other metal salts or by impregnation, etc., coprecipitation ispreferred.

The total B.E.T. surface area of the catalyst will preferably range fromabout 150 to about 350 m² /g of catalyst, more preferably from about 225m² /g to about 335 m² g. When nickel is the metal used to prepare thecatalyst, the reduced nickel surface area of the calcined catalyst willbe greater than about 50 m² /g, preferably greater than about 55 m² /gand may be as high as 100 m² /g or more. Generally the reduced nickelsurface area of the calcined catalyst will range from about 55 to about75 m² /g, and more often from about 60 to about 75 m² /g.

The catalysts of the present invention are useful for hydrogenatinghydrogenatable organic compounds such as aromatic compounds, aldehydes,alcohols, edible fats and oils, aromatics in white oil base stock, nitrocompounds, nitriles, and unsaturated and substituted hydrocarbons. Thecatalysts can also be used in an oxo process for producing alcohols,aldehydes, etc., as well as being used as a pollutant scavenger for suchpollutants as nitrogen oxides.

DETAILED DESCRIPTION OF THE INVENTION

The catalysts of the present invention are produced by preparing aheated aqueous reaction mixture containing aluminum anions, solid porousparticles and metal ions selected from the group consisting of thenon-ferrous metals of Group VIII of the Periodic Table of the Elementsand precipitating the aluminum anions and metal ions with the solidporous particles. All reference to the Periodic Table of the Elementsherein refers to the Periodic Table of the Elements illustrated in theinside covers of the 55th Edition of the Handbook of Chemistry andPhysics published by CRC Press (1974). Typical non-ferrous Group VIIImetals useful in the practice of the invention include nickel, cobalt,platinum, iridium, palladium, rhenium, rhodium and ruthenium. Nickel andcobalt are the preferred non-ferrous Group VIII metals, and nickel isthe most preferred.

The coprecipitated catalysts of the present invention can be prepared byvarious techniques. For example, all the components of the reactionmixture (e.g., the metal salts and solid porous carrier particles) maybe placed in a suitable reaction vessel under acidic conditions andthereafter the hydroxyl ion concentration is increased while heating andagitating the slurry. In connection with this technique, reference ismade to U.S. Pat. No. 4,113,658, the disclosure of which is incorporatedherein by reference. Another technique involves dissolving the metalsalts (e.g., nickel nitrate and aluminum nitrate) in water underagitation and at elevated temperatures, preferably ranging from 60° C.up to the solution's boiling point at atmospheric pressure. Highertemperatures may be employed provided that the solution is underpressure. The solid porous particles are then added to this agitated andheated reaction mixture. Generally, the dissolved metal ions in thereaction mixture will be kept below about 0.6 mols/liter. This dilutionof the dissolved metal ions is one preferred means for obtaining highcatalytic activity. Preferably, a precipitating agent is added to theheated reaction mixture to aid in the coprecipitation of the non-ferrousGroup VIII metal with the aluminnum ions and porous support particles.

During catalyst preparation, water may be added to the reaction mixtureto maintain a nearly constant volume so that water loss by evaporationis continually replaced. The aqueous reaction mixture is preferably keptat elevated temperatures, e.g., from about 60° C. up to about theboiling point of the solution (at atmospheric pressure) for a period ofone to five hours. Heating at a temperature below the boiling point ofthe solution, i.e., 60°-99° C., may be employed to minimize evaporation.The reaction mixture is then filtered and the resulting product iswashed, preferably several times repeatedly with boiling water, toremove alkali metals and other impurities. (Generally the washings willbe four or more times.) The catalyst is then dried at temperaturesranging from 90°-200° C., for one to five hours and calcined from anoxygen source, e.g., an oxygen-containing gas such as air to atemperature ranging from about 300°-450° C., for a period of about 2-8hours, preferably about 3-5 hours. The finished catalyst can then bereduced or charged directly (or subsequent to shaping or extruding suchas in the form of tablets or pellets) into the reaction vessel, withoutactivation, and activated in the reaction vessel with a gaseousreductant, usually flowing hydrogen. Alternatively, the catalyst may beprereduced and passivated (stabilized) prior to charging into thereactor.

As stated previously, it is preferred that in preparing the catalyst ofthis invention, the coprecipitation of the catalyst is made from dilutesolutions, i.e., the solution should have a metal concentration nogreater than about 1.0 mol/liter and an aluminum nitrate concentrationno greater than about 0.4 mols/liter. The most preferred solution usedin preparing the catalyst has no more than about 0.75 mols/liter ofmetal ions, more preferably less than about 0.6 mols/liter and about0.26 mols/liter of aluminum ions, e.g., aluminum nitrate. Such dilutesolutions insure high metal surface area. This is contrasted with a moreconcentrated precipitation in which the solution contains up to twice asmuch solute. The mole ratio of metal to aluminum employed ranges fromabout 0.3:1 to about 2.5:1 in the calcined and reduced catalyst.

In the case of the aluminum porous alumina based catalysts about 30 to90 wt. % of the total alumina content of the activated catalyst isderived from precipitated aluminum ions when the solid porous particlesare comprised of alumina. Preferably, however, 50 to 70 wt. % of thetotal alumina content is derived from the aluminum ions when the solidporous particles are comprised of alumina.

The remaining steps in preparing and activating the catalyst areidentical to those described above.

In a preferred aspect of the present invention, the catalyst is formedby coprecipitating, from an aqueous solution, aluminum ions and one ormore metals selected from the group consisting of nickel or cobalt ontoa solid porous particulate support, preferably solid porous silicaand/or alumina, more preferably solid porous alumina.

When cobalt is the metal selected for the use herein, its source may beany of the following non-limiting examples: cobaltous nitrate, cobaltouschloride and cobaltous bromide.

When the selected metal is nickel, its source may include thenon-limiting group selected from nickel nitrate, nickel chloride andnickel bromide.

Non-limiting examples of sources of aluminum ions suitable for useherein include aluminum nitrate, aluminum sulfate, aluminum chloride.Preferably the source of the aluminum ions is aluminum nitrate.

Other sources of metal ions as well as aluminum ions may be utilized andmay be determined by one having ordinary skill in the art by eitherroutine experimentation or general knowledge in the art. For example,the salts of the metals used herein are the water-soluble salts such asnitrates, halides, formates or oxalates.

Non-limiting examples of solid porous particles suitable for use hereininclude alumina, kieselguhr, infusorial earth, diatomaceous earth,siliceous earth and silica. Preferred is alumina particles, morepreferred is eta and gamma alumina particles, and most preferred isgamma alumina particles. The concentration of the solid porous particlescan be expressed as percent of total alumina or silica in the catalystand may range from about 10 wt. % to about 70 wt. %, preferably fromabout 30 wt. % to about 50 wt. %.

It is preferred, especially in the case of nickel and/or cobalt, thatthe coprecipitation of these ions with aluminum ions in aqueous solutioncontaining the solid porous particles be completed by the addition of awater soluble alkaline precipitating agent. The alkaline ammoniumprecipitants such as ammonium bicarbonate or ammonia are most suitablefor minimizing the amount of alkali metal residue which has to beremoved by washing to avoid poisoning action on the finished catalyst.In some instances, the potassium precipitants may be used where thepotassium acts as a promoter rather than a poison. Sodium carbonate isanother example of a suitable water-soluble alkaline precipitatingcompound. Various organic alkaline materials such as urea, and primaryand secondary amines may be used to complete the precipitation. However,a preferred precipitating agent is ammonium bicarbonate.

The precipitated catalyst is preferably washed to remove impurities,particularly sodium. If it is desired to remove the trace levels ofsodium in the catalyst, one may wash the filter cake with a washingliquor comprising a mixture of water and a small amount, i.e., about 100ppm of a filtering aid such as sodium or potassium carbonate or nitrateor 200 ppm of ammonium carbonate. In this connection, reference is madeto U.S. Pat. No. 4,105,591, the disclosure of which is incorporatedherein by reference.

After the washing, drying and calcining is completed, the catalyst mustbe reduced in order to activate it. Reduction is carried out in thepresence of a reducing gas, preferably hydrogen. The reducing gas ispassed over the catalyst at ambient temperature at a rate of about 5liters/hr/gm to about 30 liters/hr/gm and then the temperature is raisedto a range of from about 75° C. to about 450° C., preferably from about195° C. to about 400° C.

The reduction (activation) may be carried out after the catalyst hasbeen loaded into the reaction vessel where the hydrogenation will becarried out, which may be either batch or continuous. The nature of thereactor will be obvious to one skilled in the art. The activationprocedure of U.S. Pat. No. 4,088,603 may be used with the catalyst ofthe present invention.

The activated catalyst is sensitive to deactivation and may not bestored in the presence of oxygen at ordinary temperatures without firstbeing passivated. The passivation step may consist of purging thereactor at a temperature greater than about 150° C. with an inert gas,preferably nitrogen, cooling to ambient temperature and then passing theinert gas over the catalyst while an air bleed is introduced into theinert gas so as to have approximately 1-2 mol percent oxygen present.This procedure will passivate the catalyst by putting a surface oxidecoating on it. Preferably, the catalyst will be passivated by theprocess of U.S. Pat. No. 4,090,980, the disclosure of which isincorporated herein by reference.

The B.E.T. total surface area of the catalyst of the present inventionwill generally range from about 150 to about 350 m² /g, preferably fromabout 225 m² /g to about 325 m² /g. The method for measuring the totalcatalyst surface area known as the B.E.T. method is described in Emmett,P. H., Advances in Catalysis, I. 65, (1948). Also, the catalystpreferably contains about 0.1 wt. % or less sodium based on the totalweight of the catalyst.

Where nickel is chosen as the metal herein, the resulting catalyst iscapable of having a nickel surface area ranging from about 55 to 100 m²/g as determined by hydrogen chemisorption after reduction at 400° C.,unless otherwise specified, in the manner described by Yates, Taylor andSinfelt in J. Am Chem. Soc., 86, 2996 (1964), the disclosure of which isincorporated herein by reference. Also, the catalyst preferably containsabout 0.1 wt. % or less of sodium and preferably from about 25 wt. % toabout 50 wt. % nickel based on the total weight of the catalyst.

Where cobalt is chosen as the metal herein, the resulting catalyst iscapable of having a cobalt surface area ranging from about 5 to about 20m² /g as determined by hydrogen chemisorption (discussed above) afterreduction at 400° C. unless otherwise specified. Also, the catalystpreferably contains about 0.1 wt. % or less sodium and preferably fromabout 25 wt. % to about 60 wt. % of cobalt wherein all weight percentsare based on the total weight of the catalyst.

The catalysts of the instant invention are useful in hydrogenatinghydrogenatable organic compounds. In this connection, the catalysts ofthe instant invention may be used to hydrogenate aromatic containingcompounds as typified by the hydrogenation of benzene to cyclohexane,the hydrogenation of aldehydes, both saturated and unsaturated to thealcohols as in the well-known oxo process, the hydrogenation of thedouble bonds in edible fats and oils as well as other olefins bothstraight and branched chain, the hydrogenation of aromatics in white oilbase stock to produce high-grade white oil, the hydrogenation of nitrocompounds to amines and the hydrogenation of nitriles to amines. Indeed,olefins as used herein signify unsaturated compounds having at least onemultiple bond and contemplates polyunsaturated compounds as well.

The conditions for the hydrogenation reactions have been discussed verywidely and are well known to those skilled in the art; broadly thefollowing conditions may be utilized: temperatures ranging from about25° C. to 300° C., preferably from 75° C. to 250° C.; pressures rangingfrom 1 atmosphere to 800 atmospheres, preferably from 1 atmosphere to 50atmospheres; feed rates of from 0.2 to 100 volumes per hour per volumeof catalyst and hydrogen addition of from 500 to 10,000 standard cubicfeet per barrel (SCF/B) of feed may be used.

In the case of the oxo process, i.e., the addition of carbon monoxideand hydrogen to alkene to produce alcohols, aldehydes and otheroxygenated organic compounds, one would typically employ conditions suchthat the temperatures would range from about 70° C. to 175° C. and use ahydrocarbon mole ratio of 0.5 to 10 and a pressure of 100 to 1000 psig.The alkenes used in such a process would typically contain 2 to 20carbon atoms. The product of such a carbonylation process generallyconsists of aldehydes, acetals, unsaturated oxygenated materials and thelike which require hydrofinishing in a second or further hydrogenationstage. It is to the treatment of the aldehyde product, in particular,that the present invention applies. Hydrogenation conditions in thisfurther reaction stage follow those generally employed in the firststage.

Another useful improved hydrogenation is the conversion of aromatics inwhite spirits to yield high quality solvents. The upgrading of whitespirits by the process of the instant invention is an improvement in thetreatment of such materials.

Still another useful improved hydrogenation of the invention is theconversion of olefins in paraffin solvents such as denonenizer bottomsand deoctenizer overheads.

Two especially useful hydrogenation processes included within the scopeof the invention include the hydrogenation of aromatics such as benzeneto cyclohexane and the production of amines from nitro compounds andnitriles. For example, the invention is useful in converting C₁₂ to C₂₄nitriles to the corresponding fatty acid amines. Also, aromatic nitrocompounds may be converted to amines, e.g., nitrobenzene to aniline orthe conversion of aromatic amines to cycloaliphatic amines, e.g.,aniline to cyclohexane amine.

The following examples serve to more fully describe the manner of makingand using the above-described invention, as well as to set forth thebest modes contemplated for carrying out various aspects of theinvention. It is understood that these examples in no way serve to limitthe true scope of this invention, but rather, are presented forillustrative purposes.

EXAMPLE 1

Catalyst A was prepared as follows: 62.9 g of Ni-(NO₃)₂.6H₂ O and 33.1 gAl(NO₃)₃.6H₂ O was dissolved in 560 ml of distilled water. The solutionwas heated to about 80° C. (but below the boiling point of the reactionmixture) and 2.8 g of solid porous particles of gamma alumina was added.The slurry had an acidic pH of 4. With rapid stirring, 52.4 g of the NH₄HCO₃ precipitating agent was added as fast as foaming would allow. Thereaction mixture was maintained at the elevated temperature for 3 hours.The coprecipitated catalyst was filtered and washed by reslurrying 3times with 2 liters of hot (>80° C.) distilled water. The resultingfilter-cake was dried overnight at 110° C. and calcined for 3 hours at400° C., the catalyst was reduced for 16 hours in hydrogen at 400° C.and had a calculated nickel content of 63.5 wt. % based on the totalweight of the reduced catalyst. The resulting catalyst was also found tohave a B.E.T. surface area of 240 m² /g and reduced nickel surface areaof 63.2 m² /g. This catalyst was then used to hydrogenate benzene tocyclohexane, the results of which are shown in Table I.

COMPARATIVE EXAMPLE

Catalyst B was prepared as follows: 112 g of Ni(NO₃)₂.6H₂ O wasdissolved in 500 ml of distilled water, then 38 g of Na₂ SiO₃.9H₂ O wasdissolved in another 500 ml of water and 5 g of acid washed kieselguhrwas slurried in the second solution. The second solution with kieselguhrslurried therein was stirred vigorously while the first solutioncontaining the nickel salt was added to a uniform rate over a 20-minuteperiod. This mixture was then heated to the boiling point of the mixture(at atmospheric pressure) and 80 g of NH₄ HCO₃ was added to a uniformrate over a 20-minute period. The mixture was kept at the boiling pointof the reaction mixture of 3 hours while stirring continued. It was thenfiltered and washed 5 times with boiling water, each wash consisting of500 ml of distilled water. The filter cake was then dried at 120° C. andcalcined in air for 4 hours at 400° C. The reduced nickel surface areawas determined by hydrogen chemisorption, after reduction at 400° C., tobe 65 m² /g and it had a B.E.T. total surface area of 292 m² /g. Thiscatalyst was used to hydrogenate benzene to cyclohexane the results ofwhich are shown in Table I.

                  TABLE I                                                         ______________________________________                                        CATALYTIC CONVERSION -OF BENZENE TO CYCLOHEXANE.sup.(a)                                     Benzene Conversion %                                            Minutes on Stream                                                                             Catalyst A                                                                              Catalyst B                                          ______________________________________                                        30              95        63.1                                                60              90        61.8                                                90              79        61.1                                                120             76.2      57.4                                                150             75.4      --                                                  180             74.6      54.1                                                210             73.1      58.5                                                240             74.1      57.7                                                ______________________________________                                         .sup.(a) Reaction Conditions: Pressure: 1 atmosphere; Temperature:            78° C., Feed: 90% nhexane, 10% benzene; feed rate: 20 cc/hr;           H.sub.2 rate: 20.4 1/hr; catalyst charge: 0.25 gm (catalyst reduced 16 hr     at 400°  C.)?                                                     

The above table illustrates that the nickel-aluminate catalyst of thepresent invention has a higher activity for hydrogenating benzene than anickel-silicate catalyst of the prior art.

EXAMPLE 2

Catalyst C was prepared according to the procedure of Example 1 aboveexcept kieselguhr was substituted for gamma alumina as the solid poroussupport and 36 gm of sodium carbonate was used as the precipitatingagent. This catalyst was also used to hydrogenate benzene tocyclohexane. This catalyst had a B.E.T. surface area of 177 m² /g. Theresults are set forth in Table II.

EXAMPLE 3

Catalysts D and E were prepared according to Example 1 except that 3.99g of Cu(NO₃)₂.3H₂ O were dissolved in the distilled water along with thenickel nitrate and aluminum nitrate and 69.9 g of NH₄ HCO₃ was used asthe precipitating agent. In Catalyst E, 2.8 g of kieselguhr wassubstituted for the alumina as the solid porous support. Both of thesecatalysts were used to hydrogenate benzene to cyclohexane. The resultsare set forth in Table II.

EXAMPLE 4

Catalysts F and G were prepared according to Example 1 above except56.66 g of Ni(NO₃)₂.6H₂ O, 33.1 g Al(NO₃)₃.6H₂ O, and 6.27 g ofCo(NO₃)₂.6H₂ O was dissolved in 560 ml of distilled water, 69.9 g NH₄HCO₃ was used as the precipitating agent, 2.8 g gamma alumina was thesolid porous support for Catalyst F and 2.8 g of kieselguhr for CatalystG. Both catalysts were also used to hydrogenate benzene to cyclohexaneand the results are set forth in Table II.

EXAMPLE 5

Catalyst H and I were prepared according to Example 1 above except 56.6g Ni(NO₃)₂.6H₂ O, 33.1 g Al(NO₃)₃.6H₂ O, 6.27 g Co(NO₃)₂.6H₂ O and 3.99g (Cu(NO₃)₂.3H₂ O were dissolved in 560 ml of distilled water. 69.9 gNH₄ HCO₃ was used as the precipitating agent. 2.8 g of gamma alumina wasthe porous support for Catalyst H and 2.8 g kieselguhr was the poroussupport for Catalyst I. Both catalysts were used to hydrogenate benzeneto cyclohexane. The results are set forth in Table II.

COMPARATIVE EXAMPLE

For the purposes of comparison an iron containing catalyst was preparedin the following manner: 91.2 gm of Fe(NO₃)₃.9H₂ O was dissolved in 500ml of distilled water. To this solution there was added 2.8 gm ofkieselguhr followed by the addition under conditions of vigorous mixing200 ml of an aqueous solution containing 21.26 gm of Na₂ SiO₃.9H₂ O).Mixing of this comingled solution was continued and followed by heatingto about 80° C. The coprecipitation was completed by the addition of67.2 gm of ammonium bicarbonate. The mixture was mixed for an additional30 minutes after the last addition, and diluted to 4 liters with water,washed by decantation 2 times with 4 liter washes, filtered and dried at120° C. The catalyst was calcined for 3 hours at 400° C. The catalysthad an argon B.E.T. total surface area after evacuation at 260° C. of256 m² /g. After overnight reduction at 400° C., the catalyst had ametal surface determined by hydrogen chemisorption to be less than onem² /g catalyst, and an argon B.E.T. surface area of only 132 m² /g ofcatalyst.

An attempt was made to convert benzene to cyclohexane using the ironcatalyst prepared above. The reaction conditions were as follows:Pressure 1 atm; Temperature: 76°-77° C.; Feed: 90% N-hexane, 10%benzene; Feed Rate: 20 cc/hr; H₂ Rate: 20.4 liters/hour; CatalystCharge: 0.25 gms of catalyst which had been reduced 16 hours at 400° C.Samples of the product were taken at 15 minutes, 30 minutes and 60minutes and there was no sign of benzene conversion in any of thesesamples. The temperature was raised to 112° C. and the product wassampled to find no conversion of benzene to cyclohexane.

The above tests demonstrate that the non-noble metal silicacoprecipitated compositions, i.e., nickel, cobalt and iron are notequivalent in their hydrogenation catalytic properties. The ironcontaining composite prepared by the process of U.S. Pat. No. 3,697,445had substantially no detectable catalytic activity with respect toconverting benzene to cyclohexane, whereas nickel and cobalt catalystscoprecipitated with silicate ions in the presence of silica particleshave good hydrogenation catalytic activity.

                                      TABLE II                                    __________________________________________________________________________    CATALYTIC CONVERSION OF BENZENE TO CYCLOHEXANE.sup.(a)                             (Ni/ (Ni/Al/                                                                             (Ni/Al                                                                             (Ni/Co/                                                                             (Ni/Co/                                                                            (Ni/Co/Al/                                                                           (Ni/Co/Al/                                  Al/kie-                                                                            Cu/gamma                                                                            Cu/kie-                                                                            Al/gamma                                                                            Al/kie-                                                                            Cu/gamma                                                                             Cu/kie-                                Minutes                                                                            selguhr                                                                            alumina)                                                                            selguhr)                                                                           alumina)                                                                            selguhr)                                                                           alumina)                                                                             selguhr)                               on   Catalyst                                                                           Catalyst                                                                            Catalyst                                                                           Catalyst                                                                            Catalyst                                                                           Catalyst                                                                             Catalyst                               Stream                                                                             C    D     E    F     G    H      I                                      __________________________________________________________________________     60  91.4 35.3.sup.(b)                                                                        43.3 65.9  48.3 --     45.0                                   120  83.7 52.8  37.3 58.4  44.6 --     38.4                                   180  74.0 55.0  --   53.7  42.4 --     32.4                                   240  73.2 52.4  --   51.1  41.25                                                                              43.0   33.0                                   __________________________________________________________________________     .sup.(a) Reaction Conditions: pressure: 1 atmosphere; temperature:            78° C.; feed: 90% nhexane, 10% benzene; feed rate: 20cc/hr; H.sub.     rate:20.4 1/hr; catalyst charge: 0.25 g. (catalyst reduced 16 hours at        400°  C.)                                                              .sup.(b) Same as (a) above but at a temperature at 72°  C.        

This table illustrates that the nickel-aluminate catalyst of the presentinvention, even when supported on kieselguhr has a higher activity forhydrogenating benzene than similar catalyst containing one or moreadditional metals.

EXAMPLE 6

Catalyst J was prepared by dissolving 62.9 g Ni(NO₃)₂.6H₂ O (0.216moles), 3.99 g Cu(NO₃)₂.3H₂ O (0.017 moles) and Al(NO₃)₃.9H₂ O (0.167moles) in 560 ml of agitated distilled water. The agitating mixture washeated to >80° C. (but below the boiling point of the mixture). 18.5 gNH₄ HCO₃, precipitating agent, was added to the heated mixture to obtainturbidity, then 2.8 g gamma Al₂ O₃ (available from Engelhardt) was addedto the mixture. Additional NH₄ HCO₃ was added to the mixture so that thetotal amount used was 69.9 g of 2.2 moles per mole of metal in themixture. The mixture was maintained at >80° C. and mixing was continuedfor 2 hours after the final addition of precipitating agent. Theresulting coprecipitate was filtered and washed twice by reslurryingwith 2 liters of distilled water. The washed catalyst was placed in anoven to dry at 110° C. (30.35 g recovered). The dried catalyst was thenplaced in a furnace and calcined for 3 hours at 400° C. (22.6 grecovered). A sample of the catalyst was reduced overnight at 400° C.and analyzed to have a H₂ surface area (by chemisorption technique) of23.1 m² /g and a B.E.T. total surface area of 206 m² /g. The remainderof the catalyst was then reduced overnight at a temperature of 200° C.then tested for its ability to convert benzene to cyclohexane. Theresults of this test are shown in Table III below.

A similar catalyst preparation was made, identified as Catalyst K, usingthe same procedure, materials and concentrations described for CatalystJ except that kieselguhr was used in place of the Al₂ O₃ seed. Thecatalyst after being reduced overnight at 400° C. was found to have a H₂surface area (by chemisorption technique) of 32.3 m² /g. The catalystwas then tested for its catalyst hydrogenation ability and the resultsshown in Table III.

                  TABLE III                                                       ______________________________________                                        CATALYTIC CONVERSION                                                          OF BENZENE TO CYCLOHEXANE.sup.(a)                                             Minutes      (Ni/Cu/Al       (Ni/Cu/Al                                        on           gamma alumina)  kieselguhr)                                      Stream       Catalyst J      Catalyst K                                       ______________________________________                                        15           50              43.3                                             30           41.5            38.4                                             60           35.3            37.4                                             90           50.0            --                                               120          52.8            --                                               150          50.4            --                                               180          55.0            --                                               210          53.9            --                                               240          52.4            --                                               ______________________________________                                         .sup.(a) Reaction Conditions: pressure: 1 atmosphere; temperature:            78°  C.; feed: 90% nhexane, 10% benzene; feed rate: 20 cc/hr;          H.sub.2 rate: 20.4 1/hr; catalyst charge: 0.25 g.                        

This table again illustrates that the nickel-aluminate catalystunexpectedly has a relatively high hydrogenation activity.

EXAMPLE 7

Catalyst L was prepared by dissolving 56.66 g of Ni(NO₃)₂.6H₂ O, 6.27 gCo(NO₃)₂.6H₂ O, 33.1 g Al(NO₃)₃.9H₂ O and Cu(NO₃)₂.6H₂ O in 560 ml ofagitated distilled water. The agitating mixture was heated to >80° C.(but below the boiling point of the mixture). 18.5 g NH₄ HCO₃,precipitating agent, was added to the heated mixture to obtainturbidity, then 2.8 g gamma Al₂ O₃ (available from Engelhardt) was addedto the mixture. Additional NH₄ HCO₃ was added to the mixture so that thetotal amount of NH₄ HCO₃ employed was 69.9 g. The mixture was maintainedat >80° C. and mixing was continued for 2 hours after the final additionof precipitating agent. The resulting coprecipitate was filtered andwashed twice by reslurrying with 2 liters of distilled water. The washedcatalyst was placed in an oven to dry at 110° C. The dried catalyst wasthen placed in a furnace and calcined for 3 hours at 400° C. A sample ofthe catalyst was reduced overnight at 400° C. and analyzed to have a H₂surface area (by chemisorption) of 41.5 m² /g. The remaining catalystwas then reduced overnight at 200° C. and tested for its ability tohydrogenate benzene to cyclohexane using the reaction conditionsspecified in Tables I, II and III herein. After 15 minutes at 80° C.,24.3% of the benzene was converted to cyclohexane and after 30 minutesat 78° C., 17.5% of the benzene was converted to cyclohexane. Althoughthis catalyst system demonstrated a relatively low hydrogenationactivity for benzene, it was interesting to note that this hydrogenatingactivity was present even when the catalyst was activated at 200° C.rather than the conventional 400° C.

The following examples illustrate the superior hydrogenation performanceof the nickel/aluminum catalysts of the present invention which havebeen coprecipitated in the presence of solid porous particles, whencompared with nickel/aluminum catalysts which have been coprecipitatedin the absence of such particles. Thus, the importance of employingsolid porous particles is herein illustrated.

COMPARATIVE EXAMPLE

Catalyst M was prepared by dissolving 74.1 g of Ni(NO₃)₂.6H₂ O and 37 gof Al(NO₃)₃.9H₂ O in 186 ml of distilled water. 75.3 g of Na₂ CO₃(precipitating agent) was also dissolved in 200 ml of distilled water.Both solutions were heated above 90° C. (but below the boiling point ofthe solution with rapid stirring. The mixture was maintained at thattemperature, with rapid stirring for 30 minutes. The resultingcoprecipitated catalyst was filtered and washed until the pH of thefiltrate had fallen below 8. The filtrate was dried at 110° C. andcalcined for 6 hours at 450° C. A sample of the calcined catalyst wasreduced in hydrogen at 400° C. for 16 hours and was found to have ahydrogen area of 40.2 m² /g (equivalent to reduced nickel surface area).The catalyst was also found to have a B.E.T. surface area of 126 m² /g.Another sample of the catalyst was used to hydrogenate benzene tocyclohexane. The results are set forth in Table IV below.

EXAMPLE 8

Catalyst N was prepared according to the procedure used for preparingCatalyst M except 74.1 g of Ni(NO₃)₂.6H₂ O, 23.5 g of Al(NO₃)₃.9H₂ O, 50g of Na₂ CO₃, and 1.8 g of gamma Al₂ O₃ were employed. After reducing asample of the catalyst in hydrogen for 16 hours at 400° C., it was usedto hydrogenate benzene to cyclohexane. The results are set forth inTable IV below.

It was previously disclosed in this specification that the catalysts ofthe instant invention may contain up to about 10 wt. %, based on thetotal weight of the catalyst, of various additives such as metalsselected from Groups IB and IIA of the Periodic Table of the Elements. Apreferred group of such additives include the salts of the metals ofGroup IIA of the Periodic Table of the Elements. Such metals includemagnesium, barium, strontium, calcium, beryllium and radium. Mostpreferred are magnesium and barium.

The following example illustrates the superior performance of thosecatalysts of the present invention which include Group IIA metals.

COMPARATIVE EXAMPLE

Catalyst O was prepared according to the procedure used for thepreparation of catalyst M, except 74.1 g of Ni(NO₃)₂.6H₂ O, 34.6 g ofAl(NO₃)₃.9H₂ O, 57 g of Na₂ CO₃, and 1.9 g of Mg(NO₃)₂.6H₂ O wereemployed. After reducing a sample of the catalyst in hydrogen for 16hours at 400° C. it was used to convert benzene to cyclohexane. Theresults are shown in Table IV below.

EXAMPLE 9

Catalyst P was prepared according to the procedure used for preparingcatalyst M except 74.1 g of Ni(NO₃)₂.6H₂ O, 21.3 g of Al(NO₃)₃.9H₂ O, 50g of Na₂ CO₃, 1.9 g of Mg(NO₃)₂.6H₂ O, and 1.8 g of gamma Al₂ O₃ wereemployed. After reducing a sample of the catalyst in hydrogen for 16hours, it was used to convert benzene to cyclohexane. The results areshown in Table IV below.

                  TABLE IV                                                        ______________________________________                                        CATALYTIC CONVERSION                                                          OF BENZENE TO CYCLOHEXANE.sup.(a)                                                     Benzene Conversion %                                                  Minutes   Catalyst  Catalyst  Catalyst                                                                              Catalyst                                on Stream M         N         O       P                                       ______________________________________                                        15                  87.4      64.6    96.1                                    30        45.5      79.5      60.1    93.0                                    60        40.1      70.9      56.3    85.4                                    120       36.2      63.4      52.7    78.3                                    180       34.4      60.0      51.4    76.2                                    240       33.1      58.6      49.4    72.4                                    ______________________________________                                         .sup.(a) Reaction Conditions: Pressure: 1 atmosphere; Temperature:            78°  C. Feed: 90% nhexane; Feed Rate: 20 cc/hr; H.sub.2 Rate: 20.4     1/hr; Catalyst Charge: 0.25gm (catalyst reduced 16 hr. at 400°  C.     with H.sub.2).                                                           

As previously discussed, up to about 10 wt. %, based on the total weightof the catalyst after calcination and reduction, of one or more metalsselected from Group IIA of the Periodic Table of the Elements may beemployed. Preferably about 0.05 to 10 wt. %, more preferably about 0.1to 8 wt. %, and most preferably about 0.5 to 6 wt. % of one or moreGroup IIA metals are employed in the instantly claimed catalyst. It isalso preferred that the precipitating agent be sodium carbonate when theGroup IIA metal is employed. This is so because a precipitating agentsuch as ammonium bicarbonate will interact with the Group IIA metalthereby causing incomplete precipitation of the metal ions of theinstantly claimed catalyst.

What is claimed is:
 1. A supported coprecipitated catalyst comprisedof:(a) one or more metals selected from the non-ferrous metals of GroupVIII of the Periodic Table of the Elements. (b) aluminum, (c) porousparticles, and (d) one or more metals selected from Group IIA of thePeriodic Table of the Elements,said catalyst being characterized ashaving a B.E.T. total surface area ranging from about 150 to about 350m² /g, wherein the total amount of Group VIII metal in the catalystranges from about 25 wt. % to about 70 wt. %, and the total amount ofthe Group IIA metal in the catalyst is up to about 10 wt. %, bothamounts of metals being based on the total weight of the catalyst aftercalcination and reduction, and wherein said catalyst has been preparedby coprecipitating the aluminum ions, the Group IIA and Group VIII metalions with the solid porous particles.
 2. The catalyst of claim 1 whereinabout 0.1 to 8 wt. % of one or more Group IIA metals are employed. 3.The catalyst of claim 2 wherein the Group IIA metal is magnesium orbarium.
 4. The catalyst of claim 1 wherein the catalyst contains about0.1 wt. % or less of sodium based on the total weight of the activecatalyst.
 5. The catalyst of claim 1 wherein the solid porous particlesare selected from the group consisting of kieselguhr, infusorial earth,diatomaceous earth, siliceous earth, silica and alumina.
 6. The catalystof claim 5 wherein the solid porous particles are alumina.
 7. Thecatalyst of claim 6 wherein the amount of solid porous particles rangesfrom about 10 wt. % to about 70 wt. % based on the total amount ofalumina in the catalyst.
 8. The catalyst of claim 7 wherein the amountof the porous solid particles ranges from 30 wt. % to about 50 wt. %based on the total amount of alumina in the catalyst.
 9. The catalyst ofclaim 1 wherein the metal is selected from the group consisting ofnickel, cobalt and mixtures of nickel and cobalt.
 10. The catalyst ofclaim 8 wherein the metal is selected from the group consisting ofnickel, cobalt and mixtures of nickel and cobalt.
 11. The catalyst ofclaim 1 which has been reduced to an active state.
 12. A supportedcoprecipitated catalyst comprised of nickel, aluminum, magnesium, andsolid porous particles, said catalyst being characterized as having aB.E.T. total surface area ranging from about 150 to about 350 m² /gwherein the total amount of nickel in the catalyst ranges from about 25wt. % to about 70 wt. % and the total amount of magnesium in thecatalyst is up to about 10 wt. %, both amounts of said nickel andmagnesium being based on the total weight of the catalyst aftercalcination and reduction, and wherein said catalyst has been preparedby coprecipitating aluminum ions, nickel ions, and magnesium ions withthe solid porous particles.
 13. The catalyst of claim 12 wherein about0.1 to 8 wt. % of magnesium is employed.
 14. The catalyst of claim 13wherein about 0.5 to 6 wt. % magnesium is employed.
 15. The catalyst ofclaim 12 wherein the catalyst contains about 0.1 wt. % or less sodiumbased on the total weight of the active catalyst.
 16. The catalyst ofclaim 12 wherein the solid porous particles are selected from the groupconsisting of kieselguhr, infusorial earth, diatomaceous earth,siliceous earth, silica and alumina.
 17. The catalyst of claim 16wherein the solid porous particles are alumina.
 18. The catalyst ofclaim 17 wherein the amount of solid porous particles ranges from about10 wt. % to about 70 wt. % based on the total amount of alumina in thecatalyst.
 19. The catalyst of claim 18 wherein the amount of the poroussolid particles ranges from 30 wt. % to about 50 wt. % based on thetotal amount of alumina in the catalyst
 20. The catalyst of claim 12wherein the metal is selected from the group consisting of nickel,cobalt and mixtures of nickel and cobalt.
 21. The catalyst of claim 19wherein the metal is selected from the group consisting of nickel,cobalt and mixtures of nickel and cobalt.
 22. The catalyst of claim 12which has been reduced to an active state.
 23. A process for preparing asupported coprecipitated catalyst comprised of aluminum, one or morenon-ferrous metals of Group VIII, and one or more metals of Group IIA,both Groups being of the Periodic Table of the Elements, said processcomprising the steps of:(a) preparing an aqueous reaction mixturecomprised of (aa) at least one water-soluble metal salt of a metalselected from the group consisting of non-ferrous metals of Group VIIIof the Periodic Table of the Elements, (ab) at least one water-solublemetal salt of a metal selected from those of Group IIA of the PeriodicTable of the Elements, (ac) at least one water-soluble aluminum salt,and (ad) solid porous particles; (b) heating the aqueous reactionmixture; and (c) adding an alkaline precipitating agent to the heatedreaction mixture to coprecipitate aluminum ions and ions of metals fromboth aforesaid Group VIII and Group IIA, in the presence of said solidporous support particles.
 24. The process of claim 23 wherein the solidporous particles are selected from the group consisting of kieselguhr,infusorial earth, diatomaceous earth, siliceous earth, silica andalumina.
 25. The process of claim 24 wherein the solid porous particlesare alumina and the precipitating agent is selected from the groupconsisting of ammonium bicarbonate and sodium carbonate.
 26. The processof claim 25 which additionally includes the steps of drying the catalystand calcining it at a temperature ranging from about 300° to about 450°C. under oxidative conditions.
 27. The process of claim 26 whichadditionally includes the step of reducing said catalyst at atemperature ranging from about 75° C. to about 400° C. in the presenceof a reductant.
 28. The process of claim 23 wherein the Group VIII metalis one or more metals selected from the group consisting of nickel orcobalt.
 29. The process of claim 27 wherein about 0.1 to 8 wt. % of aGroup IIA metal is employed, based on the total weight of the catalystafter calcination and reduction.
 30. The process of claim 28 whereinabout 0.5 to 6 wt. % of a Group IIA metal is employed.
 31. The processof claim 30 wherein the Group IIA metal is magnesium or barium.
 32. Thecatalyst produced by the process in accordance with claim
 23. 33. Thecatalyst produced by the process in accordance with claim 31.